用freesurfer对扩散指标（FA，MD）进行VBA分析（基于体素的分析）-dt_recon

freesurfer官网–https://surfer.nmr.mgh.harvard.edu/fswiki/dt_recon
步骤：需要对3DT1图像进行renconall预处理

1. 将输入转换为 nifti（创建 dwi.nii）

2. 使用 FSL 的 eddy_correct进行涡流和运动校正，创建 dwi-ec.nii。可能需要 1-2 小时。

3. DTI GLM 拟合和张量构造。包括创建：

tensor.nii – maps of the tensor (9 frames)
eigvals.nii – maps of the eigenvalues
eigvec?.nii – maps of the eigenvectors
adc.nii – apparent diffusion coefficient
fa.nii – fractional anisotropy
ra.nii – relative anisotropy
vr.nii – volume ratio
ivc.nii – intervoxel correlation
lowb.nii – Low B
bvals.dat – bvalues
bvecs.dat – directions

Also creates glm-related images:
beta.nii - regression coefficients
eres.nii - residual error (log of dwi intensity)
rvar.nii - residual variance (log)
rstd.nii - residual stddev (log)
dwires.nii - residual error (dwi intensity)
dwirvar.nii - residua